Nitrogen Reduction: Process & Application. Presentation Outline Environmental effects of Nitrogen...

Nitrogen Reduction:Process & ApplicationNitrogen Reduction:

Process & Application

Presentation OutlinePresentation Outline• Environmental effects of Nitrogen• Health Effects of Nitrogen• The Nitrogen Cycle• What interrupts the cycle?• Applications

• Environmental effects of Nitrogen• Health Effects of Nitrogen• The Nitrogen Cycle• What interrupts the cycle?• Applications

Environmental Effects:Excess Nitrogen

Environmental Effects:Excess Nitrogen

• Increased Nitrogen in Rivers and Oceans

• Causes eutrophication of coastal waters

• Causes algal blooms

• Causes a decrease in oxygen in waters

• Killed significant numbers of fin fish and shellfish

• Increased Nitrogen in Rivers and Oceans

• Causes eutrophication of coastal waters

• Causes algal blooms

• Causes a decrease in oxygen in waters

• Killed significant numbers of fin fish and shellfish

Health Effects of Nitrates Health Effects of Nitrates

• Methemoglobinemia (Blue Baby Syndrome)

• Hyperthyroidism

• CNS malformations in newborns

• Diabetes

• Methemoglobinemia (Blue Baby Syndrome)

• Hyperthyroidism

• CNS malformations in newborns

• Diabetes

The Nitrogen CycleForms of Nitrogen

The Nitrogen CycleForms of Nitrogen

• NITROGEN GAS (N2)

• ORGANIC NITROGEN

• AMMONIA (NH3)

• NITRITE (NO2)

• NITRATE (NO3)

• NITROGEN GAS (N2)

• ORGANIC NITROGEN

• AMMONIA (NH3)

• NITRITE (NO2)

• NITRATE (NO3)

The Nitrogen CycleThe Nitrogen Cycle

NN22 – 78% of – 78% of

earth’s earth’s atmosphereatmosphere

Lightning – Lightning – High-energy High-energy

fixationfixation

NitratesNitratesNONO33--

BiologicalBiologicalFixationFixation

AmmoniaAmmoniaNHNH33

How does nitrogen get into our bodies?How does nitrogen get into our bodies?

• Plants produce organic molecules

- Amino Acids

- Proteins

- Nucleic Acids

• Animals eat plants or other animals

• Plants produce organic molecules

- Amino Acids

- Proteins

- Nucleic Acids

• Animals eat plants or other animals


NN22 – 78% of – 78% of




fixationfixation



Plants and Plants and microorganismsmicroorganismscreate proteinscreate proteins

Food ChainFood Chain

How does Nitrogen leave our bodies?How does Nitrogen leave our bodies?

• Breakdown of proteins, etc. into organic forms of Nitrogen

• Returned to the environment as excretions

• Breakdown of proteins, etc. into organic forms of Nitrogen

• Returned to the environment as excretions


NN22 – 78% of – 78% of




fixationfixation



Plants and Plants and microorganismsmicroorganismscreate proteinscreate proteins

Food ChainFood ChainDecayDecay

The Nitrogen CycleIn a denitrification wastewater treatment system

The Nitrogen CycleIn a denitrification wastewater treatment system

NN22 – 78% of – 78% of




NitritesNitritesNONO22-- Nitrifying Nitrifying

bacteriabacteria

DenitrifyingDenitrifyingBacteriaBacteria

Concentration Limits and Water Conservation

Concentration Limits and Water ConservationExample: The Jar of MarblesExample: The Jar of Marbles

•1 Liter of Water, 40 marbles1 Liter of Water, 40 marbles

•Concentration = 40 Mb/LiterConcentration = 40 Mb/Liter

What happens if you take out half What happens if you take out half of the water?of the water?

•Concentration = 80 mb/literConcentration = 80 mb/liter

What does that mean?What does that mean?• When it comes to treatment….

– A percent reduction removes the same number of marbles.– The receiving environment is accepting the same number of

marbles.

• When it comes to treatment….– A percent reduction removes the same number of marbles.– The receiving environment is accepting the same number of

marbles.

Septic Tank Effluent –Nitrogen Breakdown Example (2004)Septic Tank Effluent –

Nitrogen Breakdown Example (2004)

Total N - 80 mg/L

Org. Nitrogen 10 mg/L

NH3 (Ammonia) 70 mg/L

NO3 (Nitrate) 0 mg/L

NO2 (Nitrite) 0 mg/L

After Treatment –After Treatment –

Total N - 24 mg/L

Org. Nitrogen 5 mg/L

NH3 (Ammonia) 9 mg/L

NO3 (Nitrate) 10 mg/L

NO2 (Nitrite) 0 mg/L

Basic Steps in Nitrogen Removal Systems• Anoxic Zone

Conversion of nitrate to nitrogen gas (denitrification)

BOD removal

• Aerobic Zone BOD removal and nitrification

NITRIFICATION NITRIFICATION

Conversion of

Ammonia–Nitrogen to

Nitrate–Nitrogen

Conversion of

Ammonia–Nitrogen to

Nitrate–Nitrogen

Nitrification Process

Step 1: NH+4 + 1.5 O2

Nitrosomonas NO2 + 2H+ + H2O

Step 2: NO2 + 0.5 O2 Nirtrobacter NO3

Overall Reaction: NH+ 4 + 2 O2 NO3 + 2H+ + H2O

4.6 lbs O2/lb NH3-N

7.14 lbs alkalinity destroyed/lb NH3-N

Basic Design Considerations for Nitrogen Removal Systems

• Aerobic Zone Optimum Oxygen and Mixing Aerobic SRT for Nitrification Alkalinity & pH HRT Liquid Temperature Toxicity

Toxic Chemicals (for wastewater treatment)

Toxic Chemicals (for wastewater treatment)

• Homes: liquid fabric softeners, pine oil, and drain cleaners

• Commercial Facilities: Strong sanitizers or Quats, floor stripping waste (Zinc)

• Pesticides

• Acid and Caustic Materials

• Homes: liquid fabric softeners, pine oil, and drain cleaners

• Commercial Facilities: Strong sanitizers or Quats, floor stripping waste (Zinc)

• Pesticides

• Acid and Caustic Materials

QUATERNARY AMMONIUM COMPOUNDS

QUATERNARY AMMONIUM COMPOUNDSQUATs OR QAC

BENZALKONIUM CHLORIDE

CH3

|

Cl-Benz Ring-CH2-N-C18H37

|

CH3

QUATs OR QAC

BENZALKONIUM CHLORIDE

CH3

|

Cl-Benz Ring-CH2-N-C18H37

|

CH3

Problems with QUATs in Wastewater Treatment

Problems with QUATs in Wastewater Treatment

• Toxic/Inhibitory to Nitrifying Bacteria

- in concentrations <2 mg/l

• Non-biodegradable Organic Nitrogen

• Exponential Increase in Use

• Toxic/Inhibitory to Nitrifying Bacteria

- in concentrations <2 mg/l

• Non-biodegradable Organic Nitrogen

• Exponential Increase in Use

Quaternary Ammonium Compounds - Disinfectant

Quaternary Ammonium Compounds - Disinfectant

• Ammonium Ion with 4 Radicals Attached• Not oxidizers - Surface-active agents• Breakdown bacterial cell walls• Internal contents of bacteria leak out• Commonly used at 200 ppm• Effective at High Temperatures

• Ammonium Ion with 4 Radicals Attached• Not oxidizers - Surface-active agents• Breakdown bacterial cell walls• Internal contents of bacteria leak out• Commonly used at 200 ppm• Effective at High Temperatures

DENITIRIFICATIONDENITIRIFICATION

Denitrification is the conversion of Nitrate–Nitrogen to Nitrogen gas

through a biological process.

Denitrification is the conversion of Nitrate–Nitrogen to Nitrogen gas

through a biological process.

Denitrification Process

NO3 + organic carbon carb. bacteria N2 + CO2 + OH + H20

CO2 + OH HCO3

NO3 NO2 NO N2O N2

2.86 lbs oxygen recovered / lb NO3-N

3.57 lbs alkalinity recovered / lb NO3-N

Basic Design Considerations for Nitrogen Removal Systems

• Anoxic Zone D.O. <0.5 mg/L BOD:NO3-N Ratio HRT Mixing pH (6.5-7.5 ideally)

Carbon Source for Denitrification• Influent BOD• Endogenous Respiration• External Source

Methanol Ethanol Acetic Acid Sugar, etc. External carbon source should be:

• Easy to use• Low cost• Available• Favorable Microbial Growth

Denitrification Rate

• It varies with the source of carbon Methanol provides the highest rate Endogenous respiration provides the lowest rate

It varies with temperature

How Does One Size a System?How Does One Size a System?

• Influent Laboratory Analysis

• Experience

• Common Sense

• Influent Laboratory Analysis

• Experience

• Common Sense

Why Should I Worry About It?Why Should I Worry About It?

• “Thou Shalt Not Live By Flow Alone”

• Biological Vs. Hydraulic Loading

• “Thou Shalt Not Live By Flow Alone”

• Biological Vs. Hydraulic Loading

DesignDesign

• Source of the waste• Facility Practices• Flow Patterns (e.g. churches)• Effluent Requirements• Operational/Management Resources

• Source of the waste• Facility Practices• Flow Patterns (e.g. churches)• Effluent Requirements• Operational/Management Resources

System Loading w/ NSystem Loading w/ N

Reduce treatment expectations by 20%Reduce treatment expectations by 20%

Why? Why?

•Nitrifying bacteria are easily crowded out when Nitrifying bacteria are easily crowded out when high levels of BODhigh levels of BOD55 are present. are present.

•The bugs that reduce BODThe bugs that reduce BOD55 are stronger than those are stronger than those

that nitrify. that nitrify.

•Therefore physical space must be made available Therefore physical space must be made available for nitrifiers.for nitrifiers.

Real World ExamplesReal World Examples

• Restaurant

• Subdivision

• School

• Restaurant

• Subdivision

• School

BOD5 & TKN CalculationsBOD5 & TKN CalculationsMust convert BOD5 and TKN influent

from mg/L to lbs. /day.

= flow (gpd) x 8.34 x BOD (mg/L) = BOD5 (lbs/day) 1,000,000

= flow (gpd) x 8.34 x TKN (mg/L) = TKN (lbs/day) 1,000,000

RestaurantRestaurant

Restaurant Lbs/day <200mg/L <30 mg/LNH3

Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 1000

FOG 150

TKN 60

BOD5 CalculationBOD5 Calculation

Restaurant. Flow 1500 gpd, BOD = 1000 mg/L. Calculation:

= flow (gpd) x 8.34 x BOD5 (mg/L) = BOD5 (lbs/day) 1,000,000

= 1500 gpd x 8.34 x 1000 mg/L = ~12.5 (lbs/day) 1,000,000

TKN CalculationTKN Calculation

Restaurant. Flow 1500 gpd, TKN = 50 mg/L. Calculation:

= flow (gpd) x 8.34 x TKN (mg/L) = TKN (lbs/day) 1,000,000

= 1500 gpd x 8.34 x 60 mg/L = 0.75 (lbs/day) 1,000,000

RestaurantRestaurant

Restaurant Lbs/day <200mg/L <30 mg/LNH3

Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 1000 ~12.5

FOG 150

TKN 60 0.75

RestaurantRestaurantRestaurant Lbs/day <200mg/L <30 mg/L

NH3 Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 1000 ~12.5

FOG 150

TKN 60 0.75

SubdivisionSubdivision

Subdivision Lbs/day <200mg/L <30 mg/LNH3

Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 220

FOG 30

TKN 70

BOD5 & TKN CalculationsBOD5 & TKN Calculations

Subdivision: Flow 1500 gpd, BOD = 220 mg/L, TKN = 70 Calculation:

BOD= 1500 gpd x 8.34 x 220 mg/L = ~2.7 (lbs/day) 1,000,000

TKN= 1500 gpd x 8.34 x 70 mg/L = ~0.9 (lbs/day) 1,000,000

SubdivisionSubdivisionSubdivision Lbs/day <200mg/L <30 mg/L

NH3 Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 220 ~2.7

FOG 30

TKN 70 ~0.9

SubdivisionSubdivision

Subdivision Lbs/day <200mg/L <30 mg/LNH3

Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 220 ~2.7

FOG 30

TKN 70 ~0.9

SchoolSchool

School Lbs/day <200mg/L <30 mg/LNH3

Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 450

FOG 50

TKN 200

BOD5 & TKN CalculationsBOD5 & TKN Calculations

School: Flow 1500 gpd, BOD = 220 mg/L, TKN = 200 Calculation:

BOD= 1500 gpd x 8.34 x 450 mg/L = ~5.6 (lbs/day) 1,000,000

TKN= 1500 gpd x 8.34 x 200 mg/L = ~2.5 (lbs/day) 1,000,000

SchoolSchool

School Lbs/day <200mg/L <30 mg/LNH3

Reduction

Total Nitrogen

Reduction

Flow 1500

BOD5 450 ~5.6

FOG 50

TKN 200 ~2.5

EffluentInfluent

(Q)

FinalClarifier

Nitrified Recycle(100-400% Q)

RAS (10-100% Q)WAS

Alternative Denitrification Systems:Single-Stage Anoxic Zone (MLE)

AnoxicBasin

Aeration Basin

BODr & Nitrification

Alternative Denitrification Systems:Single-Stage Anoxic Zone

• Effluent nitrate of 8-12 mg/L without external carbon source

• Alkalinity and oxygen recovery • Influent WW should have adequate BOD to satisfy the

denitrification needs• Sensitive to the aeration tank DO and the nitrate

recirculation flow rate• Suitable for large plants

Alternative Denitrification Systems:Post Anoxic

Influent Aeration Basin

BODr & Nitrification

Anoxic Basin

AerationBasin

FinalClarifier

Carbon Feed

Alternative Denitrification Systems:Post Anoxic

• Simple to Operate Can tolerate variations in the influent nitrate Monitoring of carbon addition is not very critical No internal recirculation flows

• Can be designed to remove high influent nitrate• Requires external carbon source (cost & complexity)• Alkalinity and oxygen recoveries benefits from

denitrification process are not used within the system

Challenges of Nitrogen Removal forOn-Site Applications

• Periodic and Non-uniform Influent Flow

• Adverse Impact of High and Low Loading Rates on Nitrogen Removal

• Typically Non-Optimum Influent BOD:TKN for Denitrification Process

• Potential for unexpected toxicity in the Influent

Questions?Questions?

For More Information...For More Information...

Phone: (800) 753-FAST

Fax: (913) 422-0808

E-mail: [email protected]

Web site: www.biomicrobics.com

Phone: (800) 753-FAST

Fax: (913) 422-0808

E-mail: [email protected]

Web site: www.biomicrobics.com

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